Midmark M9/M11 Error Code C634 Leave a comment
In this article, we’re going to explain one of the many error codes that can affect your Midmark M9/Midmark M11 autoclave. This article will focus specifically on error code C634. We’ll tell you about the problem, what displays when the error occurs, its possible causes, and the course of action to take to resolve said error.
However, if you’re more of a visual learner, we have a video on this error code available here.
And if you just want to talk to someone, call our Free Tech Support at 704-966-1650 Option 3.
Display/Symptom
C634: STERILIZE MODE PRESSURE LOW
ITEMS NOT STERILE
UNPLUG / REPLUG UNIT
Causes, Checks and Actions
Possible Cause 1: Pressure Leaks
- Check: Check for loose / worn door and dam gaskets or water leaking around door. Verify door and dam gaskets are installed properly. (Replace gasket kit 1x year)
- Action: Clean / Replace gaskets.
M9 Door Gaskets OEM available here
M11 Door Gaskets OEM available here
- Check: Replacement fill / vent valve solenoid requires rectifier harness for DC coil.
- Action: Install rectifier harness.
- Check: Check for voltage flow through rectifier harness. Refer to: Fill / Vent Valve Supply Voltage Test
- Action: Replace rectifier harness.
- Check: Leaking or defective vent valve. (Check for water leaking from condensing coil spout) Perform: Vent Valve Test
- Action: Clean / Replace vent valve.
M9 Vent Valve Repair Kit OEM available here
M11 Vent Valve Repair Kit OEM available here
- Check: Leaking or defective fill valve. Check for water leaking back into reservoir thru the fill line. (Look for bubbles coming from bottom of reservoir) Perform: Fill Valve Test
- Action: Clean / Replace fill valve.
M9 Fill Valve OEM available here
M11 Fill Valve OEM available here
- Check: Leaking or defective air valve. Check for excessive steam coming thru condensing coil spout. NOTE: During the HEAT & VENT modes, it is normal for steam to be exhausted thru the spout.
- Action: Clean / Replace air valve.
M9 Air Valve OEM available here
M11 Air Valve OEM available here
- Check: Leaking or defective Pressure Relief Valve. Check for water / steam leakage from beneath the rear of the sterilizer. Perform: Pressure Relief Valve Test
- Action: Replace pressure relief valve.
M9 Safety Valve OEM available here
M11 Safety Valve OEM available here
- Check: Pressure transducer tubing leaking. Check for steam leakage at pressure transducer tubing connections.
- Action: Secure pressure transducer tubing connections with high temperature cable ties.
M9 Pressure Tubing OEM available here
M11 Pressure Tubing OEM available here
- Check: Check all plumbing fitting connections for leakage.
- Action: Tighten or replace fittings.
Possible Cause 2: Temperature sensor is malfunctioning.
- Check A: Check for residue build up on temperature sensor probe.
- Action A: Clean sensor probe with Speed-Clean, distilled water, and abrasive pad.
- Check B: Check that nothing is touching or crowding the temperature sensor. (Example: trays, pouches, cassettes, etc.)
- Action B: Reposition items so nothing touches or crowds the temperature sensor.
- Check C: Perform: Temperature Sensor Resistance Test. Allow sensor to cool to room temperature before testing. Acceptable range 1.07-1.1K Ω. Refer to: Temperature Sensor Resistance Test
- Action C: Replace temperature sensor.
M9 Temperature Sensor available here
M11 Temperature Sensor available here.
- Check D: Perform: Temperature Sensor Supply Voltage Test. Disconnect sensor harness from J12 on PC board. On pins 1 & 2 acceptable range is 4.0 – 6.0 VDC. Refer to: Temperature Sensor Supply Voltage Test
- Action D: Replace Main PC board.
M9 PC Board OEM available here
M11 PC Board OEM available here
Possible Cause 3: Sterilizer is unlevel.
- Check 1: Verify support surface is level.
- Check 2: Verify water on all sides of chamber are equal.
- Action: Place sterilizer on a level support surface.
Possible Cause 4: Facility voltage too high/low.
- Check: Test facility supply voltage. Voltage must be… 115V models: 104 – 127 VAC 50/60 Hz 230V models: 207 – 253 VAC 50/60 Hz
- Action: Contact an electrician to modify voltage.
M9 PC Board OEM available here
M11 PC Board OEM available here
As always if you have any questions about this process or anything else please feel free to contact us and take advantage of our “FREE TECH SUPPORT.”
We also offer FREE VIRTUAL TECH SUPPORT to “See and Talk” with a “Real Time Live Technician” for any problems you may be in need of help with.
You can also use our “FREE MAINTENANCE PROGRAM”. Take the guesswork and worrying about what unit is due for maintenance and which maintenance cycle it is time for. We will keep track of all your autoclaves and let you know when it’s time for anything.